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All 11 questions. After you submit, each question shows the right answer and why. Back to the quick check
The universe began as an explosion at one spot, and galaxies are flying out from the middle.
Most faraway galaxies are moving away from us.
In the raisin-bread picture of the expanding universe, what do the raisins and the dough stand for?
Using Hubble's law v = H × d with H = 22 km/s per million light-years, how fast (in km/s) is a galaxy 100 million light-years away moving away from us?
What is the cosmic microwave background?
What did the 1998 observations of distant type Ia supernovae reveal?
The redshift of a distant galaxy is best understood as its light being stretched by expanding space during the light's journey to us.
The age of the universe is close to the 'Hubble time' 1/H₀. Taking H₀ = 70 km/s/Mpc, 1 Mpc = 3.09 × 10¹⁹ km and 1 year = 3.16 × 10⁷ s, calculate 1/H₀ in billions of years (one decimal place).
Planck (with the standard ΛCDM model) gives H₀ = 67.4 km/s/Mpc and SH0ES gives 73.04 km/s/Mpc. What is the difference between them, in km/s/Mpc, to one decimal place?
Summarise the current state of the Hubble tension. Does the evidence require new physics?
How strong is the 2025 DESI evidence that dark energy changes over time?
